Change yield of production of secondary organic aerosols from isoprene

[oyvindseland]

What is the feature/what would you like to discuss?

The yield of isprene to SOA should be reduced from 5 % to 0.5 % Impact all chemistry set-up (chem_mech.doc) Should likely be default in NorESM2.3. Sara Blichner should be asked if she still think the 0.5 % is what she recommends. Added her github in the discussion section below

Is there anyone in particular you want to be part of this conversation?

@sarambl

Will this change (regression test) answers?

Yes

Will you be implementing this enhancement yourself?

Yes, but I will need some help